On Wed, 28 Oct 2009 15:33:58 -0700 Walter Keen <walter.keen@rainierconnect.net> wrote:
Most aDSL modems if set to PPPoE (I think Actiontec's come this way by default) will send the mac as the pppoe un/pw. David E. Smith wrote:
Opinions on this? I'd be interested in hearing the latest real world experience for both and the direction most folks are going in.
DOCSIS cable networks use DHCP and have for a long time. If you have Ethernet based DSLAMs, they can usually do the a number of tricks (e.g. Option 82 insertion into the DHCP request) that would make a DHCP ADSL deployment no harder (or easier) than a DOCSIS cable network. It seems to me that the fundamental purpose of PPPoE is to be able to uniquely identify the customer for billing/provisioning purposes. Even though you only need to be able to do that at the start of their session, with PPPoE you pay an 8 byte per packet overhead, on _every_ packet sent and received by the customer. Other methods of distinguishing the customer, e.g. Option 82, static DHCP mapped to a customer MAC address, or possibly 802.1x if it were available, have much, much lower overhead. I think PPPoE really only exists to make ADSL look like high speed dial-up, so that ISPs dial up backend systems didn't need to be changed when ADSL was introduced. That was a valid concern in the past, but with existing solutions or models such as the DOCSIS Cable methods, and Ethernet based DSLAMS, I'd suggest avoiding PPPoE if you can.
I can't speak to which would be better on copper specifically, but in
general I'd favor DHCP over PPPoE. Either way, most of the back-end stuff will be similar (you'll need a way to authenticate users, turn them off and on, et cetera); the differences won't be all that big. Either you're storing their MACs in a database, or their port assignments and VLAN tags, or their usernames and passwords.
With PPPoE, however, the end-user can't just plug in and go - they'll have to configure their PC, or a DSL modem, or something. That means a phone call to your tech support, most likely. In many cases, DHCP can lead to plug-and-play simplicity, which means they don't have to call you, and you don't have to answer their calls. Everyone wins. :)
David Smith MVN.net
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Walter Keen Network Technician Rainier Connect (o) 360-832-4024 (c) 253-302-0194